cancer-prevention
Recent Research Papers on
cancer-prevention
Author: Carol López de Dicastillo and María del Mar Castro-López and José Manuel López-Vilariño and María Victoria González-Rodríguez
In this work, we report the successful immobilization of green tea extract, as a natural antioxidant, on polypropylene through the incorporation of anhydride maleic grafted polypropylene on polymer formulation owing to control active compound release and prolong antioxidant activity. The extruded films were thermally characterized showing that the incorporation of green tea extract improved polymer stability, and the presence of grafted polymer did not affect polymer morphology. Green tea components release profiles depending on the type of food and polymer formulation. The use of grafted polypropylene changed the ability of the polymer to release green tea antioxidants; the amount of components released decreased with an increasing degree of grafted polypropylene. Materials were submitted to sterilization and microwave heating conditions. The immobilization of the active compounds implied a lower release during these typical food package treatments, and the available antioxidant components on the modified materials presented a good correlation with the antiradical activity toward ABTS+ radicals, prolonging their antioxidant ability.
Author: Grażyna Budryn and Dorota Żyżelewicz and Ewa Nebesny and Joanna Oracz and Wiesława Krysiak
This study investigated the influence of antioxidants of green tea aqueous extract (GTE) and green coffee aqueous extract (GCE) in concentrations of 0.25, 0.5 and 1 g·100 g− 1 on the nutritional properties of fine yeast pastry fried products such as donuts. Yeast donuts were made according to the traditional processing technology. In fried donuts physical properties (water activity, pH, hardness and color with the use of instrumental methods) as well as sensory properties were established. Moreover, quality of fat extracted from donuts (composition of fatty acids and peroxide value), content of acrylamide, composition of polyphenols and antioxidant activity were analyzed. Obtained extracts of GTE and GCE contained 26 and 41% of polyphenols, respectively, and the degree of polyphenol degradation during production of donuts was less when the dilution in dough was greater. Both tests indicated that the highest antioxidant activity had donuts with the highest analyzed addition of extract, however depending on the applied test or GTE or GCE had better antioxidant properties. Fatty acid composition was the most beneficial when the addition of GTE and GCE was on a level of 0.25 and 0.5 g·100 g− 1, respectively. In fried donuts relatively low amounts of acrylamide were obtained, amounting to 18–46 μg·kg− 1. Only the lowest addition of GTE and the highest addition of GCE caused an increase of acrylamide content in donuts, while all other levels of added extracts caused a decrease in the content of formed acrylamide.
Author: Heba-Alla H. Abd-ElSalam and Medhat A. Al-Ghobashy and Hala E. Zaazaa and Mohamed A. Ibrahim
Epigallocatechin gallate (EGCG) is a powerful antioxidant and commonly used nutraceutical. Accelerated stability of EGCG in tablet formulations was investigated. LLE and SPE were employed for sample clean-up and enrichment of EGCG over caffeine. Samples were analysed after spiking with fixed concentration of gallic acid (GA), in order to verify reproducibility of analysis. A TLC–densitometric assay was developed and validated for determination of % loss EGCG. EGCG, GA and caffeine were resolved with Rf values 0.54, 0.69 and 0.80, respectively. LC–MS/MS was used to verify identity and purity of the EGCG band. Determination was carried out over a concentration range of 0.50–5.00 μg/band and 0.20–2.40 μg/band for GA and caffeine, respectively. Results showed significant reduction in EGCG content after one, three and six months: 24.00%, 28.00% and 52.00% respectively. Results continue to demonstrate that stability of nutraceutical products should be investigated in-depth using industry-oriented protocols before granting marketing authorisation.
Author: Wanchun Wang and Yu’e Yang and Wenyi Zhang and Wenlong Wu
Summary Objectives Epidemiological studies evaluating the association of tea consumption and the risk of oral cancer risk have produced inconsistent results. Thus, we conducted a meta-analysis to assess the relationship between tea consumption and oral cancer risk. Methods Pertinent studies were identified by a search in PubMed, Web of Knowledge and Wan Fang Med Online. The fixed or random effect model was used based on heterogeneity test. Publication bias was estimated using Egger’s regression asymmetry test. Results Finally, 14 articles with 19 studies comprising 4675 oral cancer cases were included in this meta-analysis. The relative risk (95% confidence interval) of oral cancer for the highest versus the lowest category of tea consumption was 0.853 (0.779–0.934), and the association was significant between oral cancer risk and green tea consumption [0.798 (0.673–0.947)] but not in the black tea consumption [0.953 (0.792–1.146)]. The associations were also significant in Asian and Caucasian. Conclusions Our analysis indicated that tea consumption may have a protective effect on oral cancer, especially in green tea consumption.
Author: Narendra Chaudhary and Jyoti Bhardwaj and Hyo Jin Seo and Min Yong Kim and Tai Sun Shin and Jong Deog Kim
Tea fruit peel is an agricultural waste of tea manufacturing industry that contains phenols with high antioxidant activities. This study examined the effect of green tea fruit peel extract (PE) against angiogenesis and obesity. We found that PE significantly inhibited the tubular formation of human umbilical vein endothelial cells (HUVECs). Epigallocatechin gallate (EGCG), epigallocatechin (EGC) and saponin were the functional components present in PE that contributed to significant anti-angiogenesis effect. Administration of PE (100 mg/kg/d) significantly decreased the body weight in rats fed high-fat diet (HFD) whereas the food intakes between HFD and PE treatment groups were not significantly different. White adipose tissue fat-pad weights were markedly reduced in rats fed HFD plus PE compared to those in HFD group. These results showed the potential of green tea fruit peel extract in preventing angiogenesis and obesity.
Author: Gema Morales and Maribel Jimenez and Oscar Garcia and María Remedios Mendoza and Cesar Ignacio Beristain
The objective of the present work was to evaluate the effect of natural extracts on the formation of acrylamide in fried potatoes. The aqueous extracts used were obtained from wild oregano (Origanum vulgare), thyme (Thymus vulgaris), cinnamon (Cinnamomum verum), bougainvillea (Bougainvillea spp) and green tea (Camellia sinensis), which presented a high percentage of free radical inhibition (DPPH) (48–99%) and content of total phenolic compounds (205–547 μg EAG/μg of d.w.). Potatoes were submerged in the antioxidant extracts at a concentration of 1 g/L for 1 min, before being fried and their acrylamide concentration quantified by GC–MS. The extracts from green tea, cinnamon and oregano reduced the acrylamide level by 62%, 39% and 17%, respectively. The potatoes submerged in cinnamon and bougainvillea extracts showed differences in the color parameters compared to the control potatoes (P < 0.05); however, no significant differences (P > 0.05) were found in the texture and the peroxide values. The sensorial evaluation showed that the acceptance of the potatoes was not affected by the treatment applied. Thus, we can conclude that pre-treating potatoes with antioxidants before frying produces beneficial effects such as a reduction in acrylamide content, without any significant changes in their physicochemical, sensorial and textural properties.
Author: Georgia Soultani and Vasiliki Evageliou and Antonios E. Koutelidakis and Maria Kapsokefalou and Michael Komaitis
The effect of pectin on the antioxidant capacity and phenolic content of black, green, mountain tea and Pelargonium purpureum infusions was investigated. Antioxidant capacity was determined by the Ferric Reducing Antioxidant Power (FRAP) assay and total phenolics by the Folin-Ciocalteu method. Green tea was the richest in phenolics and had the highest antioxidant capacity, followed by black and the remaining two infusions. High methoxy pectin, added at various concentrations, did not affect the studied properties of all the infusions. As a further step, milk, lemon juice or sugars (sucrose, fructose) were added to black and green tea infusions, in the presence and absence of pectin. For green tea infusions, no significant differences were reported for the studied properties, for all the constituents, both in the presence and absence of pectin. For black tea infusions statistically different values were observed when pectin was combined with the constituents. These results suggest that pectin does not mask the antioxidant capacity of tea infusions and therefore, it may be added to tea infusions for stabilizing or thickening reasons and create new food formulations with improved health benefits.
Author: M.W. Korir and F.N. Wachira and J.K. Wanyoko and R.M. Ngure and R. Khalid
Several studies have demonstrated that tea flavonoids protect cells and tissues against free radicals which have been implicated in the etiology of oxidative stress-related disease disorders. However, black tea is commonly consumed with additives that could otherwise affect the bioavailability of the active tea molecules. In this study, the biochemical parameters of Kenyan teas were determined and the effect of added milk and sweeteners on the antioxidant activity of Kenyan teas was investigated. The effect of tea antioxidants on glutathione (GSH) was also evaluated in vivo in a time series study using Swiss mice. Green teas had the highest levels of total polyphenols, total and individual catechins, while black teas had high levels of total thearubigins, total theaflavins and theaflavin fractions. The antioxidant activity was high in green teas though some of the black teas were as efficacious as the green teas. The addition of milk, sugar and honey significantly (p < 0.05) decreased the antioxidant activity of tea in a concentration-dependent manner. Addition of the sweetener, stevia (Stevia rebaudiana Bertoni), showed no significant (p > 0.05) influence on the antioxidant activity of tea and therefore can be recommended as a preferred sweetener for tea. Significantly (p < 0.001) higher levels of GSH were observed in plasma than in other tissues. GSH levels were generally highest 2 h after tea consumption, which indicates the need to repeatedly take tea every 2 h to maximise its potential health benefits.
Author: Ana-Maria Manea and Bogdan Stefan Vasile and Aurelia Meghea
In this paper, the preparation and characterization of some novel nanostructured lipid carriers for drug delivery are reported. They are obtained by mixing two solid lipids, cetyl palmitate and glyceryl stearate, with three types of vegetable oils: grape seed oil, St. John's wort oil (Hypericum perforatum oil) and sea buckthorn oil. In order to increase their antioxidant and antimicrobial properties, they are co-loaded with green tea extract by using a modified high shear homogenization technique. Size distribution and polydispersity index of the developed nanostructured lipid carriers determined by the dynamic light scattering, and corroborated with the results obtained by the transmission electron microscopy analysis, confirmed that the structures obtained are at nanoscales. The crystallinity behavior of the prepared nanostructured lipid carriers has been studied by differential scanning calorimetry; zeta potential measurements show that all loaded nanostructures present excellent physical stability. Their antioxidant and antimicrobial properties evaluated by an appropriate in vitro analysis using the chemiluminescence method, and the diffusion disc method, respectively, show that green tea extract could be utilized as a valuable natural source of antioxidant and antimicrobial agent. These new nano-formulations proved to have significant potential for nutritional and pharmaceutical applications.
Author: Mariana von Staszewski and Victor M. Pizones Ruiz-Henestrosa and Ana M.R. Pilosof
Green tea polyphenols have a good antioxidant capacity but poor interfacial activity. β-lactoglobulin (β-lg) was used as an emulsifier agent and also as a carrier molecule by spontaneous nanocomplexes formation with green tea polyphenols. Oil-in-water emulsions containing liver fish oil rich in ω-3 fatty acids were formulated using these nanocomplexes at pH 6. The interfacial behavior of these complexes showed that both surface pressure and dilatational properties decreased as compared with pure β-lg. However, the initial droplet size and stability of emulsions were improved in the presence of the nanocomplexes. Moreover, the oxidative stability of liver fish oil was improved by the presence of polyphenols.